What is the interpretation of bs of dd in terms of predicting the disk performance of other I/O bound programs?

[Peng Yu]

Hi,

Many people use dd to test disk performance. There is a key option dd,
which I understand what it literally means. But it is not clear how
there performance measured by dd using a specific bs maps to the disk
performance of other I/O bound programs. Could you anybody let me know
the interpretation of bs in terms of predicting the performance of
other I/O bound programs? Thanks.

-- 
Regards,
Peng